Metabolic trade-offs in Desulfosporosus meridiei: dose-dependent FeS nanoparticles modulate extracellular electron transfer and gene expression for mineral transformation

Abstract

Biogenic ferrous sulfide nanoparticles (FeS NPs) regulate sulfate (SO42−)-reducing bacteria (SRB)-driven iron/sulfur cycling in SO42−-rich anaerobic environments, yet their dose-dependent impacts on SRB metabolism remain unclear. This study revealed how FeS NPs dose modulates Desulfosporosus meridiei (a model SRB) in reducing schwertmannite (Sch). SRB preferentially reduced Fe(III) over SO42− in Sch via FeS NPs-mediated extracellular electron transfer (EET). At low FeS doses (0–6 mM), the dsr gene expression (sulfur metabolism) associated with mineral transformation increased despite a decline in SRB abundance, accompanied by a significant enhancement in Fe(III) reduction rate, yielding siderite and pyrite as dominant products. This enhancement was attributed to FeS NPs acting as electron conduits, as evidenced by a 4–9-fold surge in bio-current intensity. However, at high FeS doses (≥6 mM), nanoparticle aggregation formed a relatively thick mineral encrustation on cell surfaces, blocking EET pathways and leaving goethite as a residual phase. Strikingly, SRB exhibited a metabolic trade-off, suppressing population growth to amplify dsr-driven electron flux under FeS stress. This adaptive strategy underscored SRB's resilience in FeS-rich environments while highlighting dose-dependent bifurcations in mineral transformation pathways. This study provided a new insight into manipulating SRB-dominated biogeochemical processes by controlling FeS NPs dose.

Graphical abstract: Metabolic trade-offs in Desulfosporosus meridiei: dose-dependent FeS nanoparticles modulate extracellular electron transfer and gene expression for mineral transformation

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Article information

Article type
Paper
Submitted
22 Apr 2025
Accepted
16 Jun 2025
First published
24 Jun 2025

Environ. Sci.: Processes Impacts, 2025, Advance Article

Metabolic trade-offs in Desulfosporosus meridiei: dose-dependent FeS nanoparticles modulate extracellular electron transfer and gene expression for mineral transformation

C. Ke, Y. Deng, S. Zhang, Q. Yao, R. Wu, Y. Bao, X. Jin, C. Guo and Z. Dang, Environ. Sci.: Processes Impacts, 2025, Advance Article , DOI: 10.1039/D5EM00310E

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